A lot of fault recording devices are installed in a power grid, once a fault occurs, the fault recording devices would start and record fault data including voltage and current instantaneous values of the three-phase a, b, c and the zero sequence, tens to hundreds of values are recorded in each cycle, and hundreds of fault occur in each province power grid every year thereby generating massive fault recording data.
On the other hand, as parameters error of an electric element is relatively large, it is necessary to extract parameters from the fault recording data. However, problems due to that the fault current contains direct current (DC) decay component, the three-phase parameters are inconsistent and the recording data is not synchronized, etc. cause large errors of the fault recording data, the decomposed sine component and the extracted line positive or negative zero sequence parameters, and requirements for the power grid computing or analyzing cannot be satisfied.